Abstract
We achieved considerable laser diode (LD) improvement after annealing InGaP/InAlGaP laser structure at 950°C for a total annealing time of 2 min. The photoluminescence intensity is increased by 10 folds and full-wave at half-maximum is reduced from ∼30 to 20 nm. The measured LDs exhibited significantly reduced threshold current (Ith), from 2 to 1.5 A for a 1-mm long LD, improved internal efficiency (ηi), from 63% to 68%, and increased internal losses αi, from 14.3 to 18.6 cm−1. Our work suggests that the use of strain-induced quantum well intermixing is a viable solution for high-efficiency AlGaInP devices at shorter wavelengths. The advent of laser-based solid-state lighting (SSL) and visible-light communications (VLC) highlighted the importance of the current findings, which are aimed at improving color quality and photodetector received power in SSL and VLC, respectively, via annealed red LDs.
Highlights
Red laser diodes (LDs) emitting in the range of 630 to 690 nm are constructed from InGaP/ InAlGaP laser structures
We studied the effect of annealing on PL peak, PL intensity, the threshold current (Ith), internal efficiency ηi, and optical losses hαii
The focus in this paper is on the performance of LD after a low degree of intermixing, limited to 5-nm blueshift
Summary
Red laser diodes (LDs) emitting in the range of 630 to 690 nm are constructed from InGaP/ InAlGaP laser structures. Increasing the Al content x to more than 0.1 severely reduces the optical efficiency of the material due to oxygen-related deep-level defects and increases the threshold current of LDs.[3,4,5]. The reason for this low efficiency is that Al is a reactive element that oxidizes even in a veryhigh vacuum and high-temperature growth environment. Increasing the Al content during growth to create efficient devices is the primary obstacle to producing efficient LEDs and LDs with Al-rich active layers. We studied the effect of annealing on PL peak, PL intensity, the threshold current (Ith), internal efficiency ηi, and optical losses hαii
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